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574 commits

Author SHA1 Message Date
Bryan Cutler 209b9361ac [SPARK-20791][PYSPARK] Use Arrow to create Spark DataFrame from Pandas
## What changes were proposed in this pull request?

This change uses Arrow to optimize the creation of a Spark DataFrame from a Pandas DataFrame. The input df is sliced according to the default parallelism. The optimization is enabled with the existing conf "spark.sql.execution.arrow.enabled" and is disabled by default.

## How was this patch tested?

Added new unit test to create DataFrame with and without the optimization enabled, then compare results.

Author: Bryan Cutler <cutlerb@gmail.com>
Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19459 from BryanCutler/arrow-createDataFrame-from_pandas-SPARK-20791.
2017-11-13 13:16:01 +09:00
hyukjinkwon 695647bf2e [SPARK-21640][SQL][PYTHON][R][FOLLOWUP] Add errorifexists in SparkR and other documentations
## What changes were proposed in this pull request?

This PR proposes to add `errorifexists` to SparkR API and fix the rest of them describing the mode, mainly, in API documentations as well.

This PR also replaces `convertToJSaveMode` to `setWriteMode` so that string as is is passed to JVM and executes:

b034f2565f/sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala (L72-L82)

and remove the duplication here:

3f958a9992/sql/core/src/main/scala/org/apache/spark/sql/api/r/SQLUtils.scala (L187-L194)

## How was this patch tested?

Manually checked the built documentation. These were mainly found by `` grep -r `error` `` and `grep -r 'error'`.

Also, unit tests added in `test_sparkSQL.R`.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #19673 from HyukjinKwon/SPARK-21640-followup.
2017-11-09 15:00:31 +09:00
ptkool d01044233c [SPARK-22456][SQL] Add support for dayofweek function
## What changes were proposed in this pull request?
This PR adds support for a new function called `dayofweek` that returns the day of the week of the given argument as an integer value in the range 1-7, where 1 represents Sunday.

## How was this patch tested?
Unit tests and manual tests.

Author: ptkool <michael.styles@shopify.com>

Closes #19672 from ptkool/day_of_week_function.
2017-11-09 14:44:39 +09:00
Bryan Cutler 1d341042d6 [SPARK-22417][PYTHON] Fix for createDataFrame from pandas.DataFrame with timestamp
## What changes were proposed in this pull request?

Currently, a pandas.DataFrame that contains a timestamp of type 'datetime64[ns]' when converted to a Spark DataFrame with `createDataFrame` will interpret the values as LongType. This fix will check for a timestamp type and convert it to microseconds which will allow Spark to read as TimestampType.

## How was this patch tested?

Added unit test to verify Spark schema is expected for TimestampType and DateType when created from pandas

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #19646 from BryanCutler/pyspark-non-arrow-createDataFrame-ts-fix-SPARK-22417.
2017-11-07 21:32:37 +01:00
Marco Gaido e7adb7d7a6 [SPARK-22437][PYSPARK] default mode for jdbc is wrongly set to None
## What changes were proposed in this pull request?

When writing using jdbc with python currently we are wrongly assigning by default None as writing mode. This is due to wrongly calling mode on the `_jwrite` object instead of `self` and it causes an exception.

## How was this patch tested?

manual tests

Author: Marco Gaido <mgaido@hortonworks.com>

Closes #19654 from mgaido91/SPARK-22437.
2017-11-04 16:59:58 +09:00
hyukjinkwon 41b60125b6 [SPARK-22369][PYTHON][DOCS] Exposes catalog API documentation in PySpark
## What changes were proposed in this pull request?

This PR proposes to add a link from `spark.catalog(..)` to `Catalog` and expose Catalog APIs in PySpark as below:

<img width="740" alt="2017-10-29 12 25 46" src="https://user-images.githubusercontent.com/6477701/32135863-f8e9b040-bc40-11e7-92ad-09c8043a1295.png">

<img width="1131" alt="2017-10-29 12 26 33" src="https://user-images.githubusercontent.com/6477701/32135849-bb257b86-bc40-11e7-9eda-4d58fc1301c2.png">

Note that this is not shown in the list on the top - https://spark.apache.org/docs/latest/api/python/pyspark.sql.html#module-pyspark.sql

<img width="674" alt="2017-10-29 12 30 58" src="https://user-images.githubusercontent.com/6477701/32135854-d50fab16-bc40-11e7-9181-812c56fd22f5.png">

This is basically similar with `DataFrameReader` and `DataFrameWriter`.

## How was this patch tested?

Manually built the doc.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #19596 from HyukjinKwon/SPARK-22369.
2017-11-02 15:22:52 +01:00
Liang-Chi Hsieh 07f390a27d [SPARK-22347][PYSPARK][DOC] Add document to notice users for using udfs with conditional expressions
## What changes were proposed in this pull request?

Under the current execution mode of Python UDFs, we don't well support Python UDFs as branch values or else value in CaseWhen expression.

Since to fix it might need the change not small (e.g., #19592) and this issue has simpler workaround. We should just notice users in the document about this.

## How was this patch tested?

Only document change.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #19617 from viirya/SPARK-22347-3.
2017-11-01 13:09:35 +01:00
hyukjinkwon 188b47e683 [SPARK-22379][PYTHON] Reduce duplication setUpClass and tearDownClass in PySpark SQL tests
## What changes were proposed in this pull request?

This PR propose to add `ReusedSQLTestCase` which deduplicate `setUpClass` and  `tearDownClass` in `sql/tests.py`.

## How was this patch tested?

Jenkins tests and manual tests.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #19595 from HyukjinKwon/reduce-dupe.
2017-10-30 11:50:22 +09:00
Takuya UESHIN 4c5269f1aa [SPARK-22370][SQL][PYSPARK] Config values should be captured in Driver.
## What changes were proposed in this pull request?

`ArrowEvalPythonExec` and `FlatMapGroupsInPandasExec` are refering config values of `SQLConf` in function for `mapPartitions`/`mapPartitionsInternal`, but we should capture them in Driver.

## How was this patch tested?

Added a test and existing tests.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19587 from ueshin/issues/SPARK-22370.
2017-10-28 18:33:09 +01:00
Bryan Cutler 17af727e38 [SPARK-21375][PYSPARK][SQL] Add Date and Timestamp support to ArrowConverters for toPandas() Conversion
## What changes were proposed in this pull request?

Adding date and timestamp support with Arrow for `toPandas()` and `pandas_udf`s.  Timestamps are stored in Arrow as UTC and manifested to the user as timezone-naive localized to the Python system timezone.

## How was this patch tested?

Added Scala tests for date and timestamp types under ArrowConverters, ArrowUtils, and ArrowWriter suites.  Added Python tests for `toPandas()` and `pandas_udf`s with date and timestamp types.

Author: Bryan Cutler <cutlerb@gmail.com>
Author: Takuya UESHIN <ueshin@databricks.com>

Closes #18664 from BryanCutler/arrow-date-timestamp-SPARK-21375.
2017-10-26 23:02:46 -07:00
hyukjinkwon d9798c834f [SPARK-22313][PYTHON] Mark/print deprecation warnings as DeprecationWarning for deprecated APIs
## What changes were proposed in this pull request?

This PR proposes to mark the existing warnings as `DeprecationWarning` and print out warnings for deprecated functions.

This could be actually useful for Spark app developers. I use (old) PyCharm and this IDE can detect this specific `DeprecationWarning` in some cases:

**Before**

<img src="https://user-images.githubusercontent.com/6477701/31762664-df68d9f8-b4f6-11e7-8773-f0468f70a2cc.png" height="45" />

**After**

<img src="https://user-images.githubusercontent.com/6477701/31762662-de4d6868-b4f6-11e7-98dc-3c8446a0c28a.png" height="70" />

For console usage, `DeprecationWarning` is usually disabled (see https://docs.python.org/2/library/warnings.html#warning-categories and https://docs.python.org/3/library/warnings.html#warning-categories):

```
>>> import warnings
>>> filter(lambda f: f[2] == DeprecationWarning, warnings.filters)
[('ignore', <_sre.SRE_Pattern object at 0x10ba58c00>, <type 'exceptions.DeprecationWarning'>, <_sre.SRE_Pattern object at 0x10bb04138>, 0), ('ignore', None, <type 'exceptions.DeprecationWarning'>, None, 0)]
```

so, it won't actually mess up the terminal much unless it is intended.

If this is intendedly enabled, it'd should as below:

```
>>> import warnings
>>> warnings.simplefilter('always', DeprecationWarning)
>>>
>>> from pyspark.sql import functions
>>> functions.approxCountDistinct("a")
.../spark/python/pyspark/sql/functions.py:232: DeprecationWarning: Deprecated in 2.1, use approx_count_distinct instead.
  "Deprecated in 2.1, use approx_count_distinct instead.", DeprecationWarning)
...
```

These instances were found by:

```
cd python/pyspark
grep -r "Deprecated" .
grep -r "deprecated" .
grep -r "deprecate" .
```

## How was this patch tested?

Manually tested.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #19535 from HyukjinKwon/deprecated-warning.
2017-10-24 12:44:47 +09:00
Takuya UESHIN b8624b06e5 [SPARK-20396][SQL][PYSPARK][FOLLOW-UP] groupby().apply() with pandas udf
## What changes were proposed in this pull request?

This is a follow-up of #18732.
This pr modifies `GroupedData.apply()` method to convert pandas udf to grouped udf implicitly.

## How was this patch tested?

Exisiting tests.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19517 from ueshin/issues/SPARK-20396/fup2.
2017-10-20 12:44:30 -07:00
Zhenhua Wang 655f6f86f8 [SPARK-22208][SQL] Improve percentile_approx by not rounding up targetError and starting from index 0
## What changes were proposed in this pull request?

Currently percentile_approx never returns the first element when percentile is in (relativeError, 1/N], where relativeError default 1/10000, and N is the total number of elements. But ideally, percentiles in [0, 1/N] should all return the first element as the answer.

For example, given input data 1 to 10, if a user queries 10% (or even less) percentile, it should return 1, because the first value 1 already reaches 10%. Currently it returns 2.

Based on the paper, targetError is not rounded up, and searching index should start from 0 instead of 1. By following the paper, we should be able to fix the cases mentioned above.

## How was this patch tested?

Added a new test case and fix existing test cases.

Author: Zhenhua Wang <wzh_zju@163.com>

Closes #19438 from wzhfy/improve_percentile_approx.
2017-10-11 00:16:12 -07:00
Li Jin bfc7e1fe1a [SPARK-20396][SQL][PYSPARK] groupby().apply() with pandas udf
## What changes were proposed in this pull request?

This PR adds an apply() function on df.groupby(). apply() takes a pandas udf that is a transformation on `pandas.DataFrame` -> `pandas.DataFrame`.

Static schema
-------------------
```
schema = df.schema

pandas_udf(schema)
def normalize(df):
    df = df.assign(v1 = (df.v1 - df.v1.mean()) / df.v1.std()
    return df

df.groupBy('id').apply(normalize)
```
Dynamic schema
-----------------------
**This use case is removed from the PR and we will discuss this as a follow up. See discussion https://github.com/apache/spark/pull/18732#pullrequestreview-66583248**

Another example to use pd.DataFrame dtypes as output schema of the udf:

```
sample_df = df.filter(df.id == 1).toPandas()

def foo(df):
      ret = # Some transformation on the input pd.DataFrame
      return ret

foo_udf = pandas_udf(foo, foo(sample_df).dtypes)

df.groupBy('id').apply(foo_udf)
```
In interactive use case, user usually have a sample pd.DataFrame to test function `foo` in their notebook. Having been able to use `foo(sample_df).dtypes` frees user from specifying the output schema of `foo`.

Design doc: https://github.com/icexelloss/spark/blob/pandas-udf-doc/docs/pyspark-pandas-udf.md

## How was this patch tested?
* Added GroupbyApplyTest

Author: Li Jin <ice.xelloss@gmail.com>
Author: Takuya UESHIN <ueshin@databricks.com>
Author: Bryan Cutler <cutlerb@gmail.com>

Closes #18732 from icexelloss/groupby-apply-SPARK-20396.
2017-10-11 07:32:01 +09:00
Takuya UESHIN af8a34c787 [SPARK-22159][SQL][FOLLOW-UP] Make config names consistently end with "enabled".
## What changes were proposed in this pull request?

This is a follow-up of #19384.

In the previous pr, only definitions of the config names were modified, but we also need to modify the names in runtime or tests specified as string literal.

## How was this patch tested?

Existing tests but modified the config names.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19462 from ueshin/issues/SPARK-22159/fup1.
2017-10-09 22:35:34 -07:00
Bryan Cutler 7bf4da8a33 [MINOR] Fixed up pandas_udf related docs and formatting
## What changes were proposed in this pull request?

Fixed some minor issues with pandas_udf related docs and formatting.

## How was this patch tested?

NA

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #19375 from BryanCutler/arrow-pandas_udf-cleanup-minor.
2017-09-28 10:24:51 +09:00
goldmedal 1fdfe69352 [SPARK-22112][PYSPARK] Supports RDD of strings as input in spark.read.csv in PySpark
## What changes were proposed in this pull request?
We added a method to the scala API for creating a `DataFrame` from `DataSet[String]` storing CSV in [SPARK-15463](https://issues.apache.org/jira/browse/SPARK-15463) but PySpark doesn't have `Dataset` to support this feature. Therfore, I add an API to create a `DataFrame` from `RDD[String]` storing csv and it's also consistent with PySpark's `spark.read.json`.

For example as below
```
>>> rdd = sc.textFile('python/test_support/sql/ages.csv')
>>> df2 = spark.read.csv(rdd)
>>> df2.dtypes
[('_c0', 'string'), ('_c1', 'string')]
```
## How was this patch tested?
add unit test cases.

Author: goldmedal <liugs963@gmail.com>

Closes #19339 from goldmedal/SPARK-22112.
2017-09-27 11:19:45 +09:00
Bryan Cutler d8e825e3bc [SPARK-22106][PYSPARK][SQL] Disable 0-parameter pandas_udf and add doctests
## What changes were proposed in this pull request?

This change disables the use of 0-parameter pandas_udfs due to the API being overly complex and awkward, and can easily be worked around by using an index column as an input argument.  Also added doctests for pandas_udfs which revealed bugs for handling empty partitions and using the pandas_udf decorator.

## How was this patch tested?

Reworked existing 0-parameter test to verify error is raised, added doctest for pandas_udf, added new tests for empty partition and decorator usage.

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #19325 from BryanCutler/arrow-pandas_udf-0-param-remove-SPARK-22106.
2017-09-26 10:54:00 +09:00
Zhenhua Wang 365a29bdbf [SPARK-22100][SQL] Make percentile_approx support date/timestamp type and change the output type to be the same as input type
## What changes were proposed in this pull request?

The `percentile_approx` function previously accepted numeric type input and output double type results.

But since all numeric types, date and timestamp types are represented as numerics internally, `percentile_approx` can support them easily.

After this PR, it supports date type, timestamp type and numeric types as input types. The result type is also changed to be the same as the input type, which is more reasonable for percentiles.

This change is also required when we generate equi-height histograms for these types.

## How was this patch tested?

Added a new test and modified some existing tests.

Author: Zhenhua Wang <wangzhenhua@huawei.com>

Closes #19321 from wzhfy/approx_percentile_support_types.
2017-09-25 09:28:42 -07:00
Liang-Chi Hsieh 3e6a714c9e [SPARK-21766][PYSPARK][SQL] DataFrame toPandas() raises ValueError with nullable int columns
## What changes were proposed in this pull request?

When calling `DataFrame.toPandas()` (without Arrow enabled), if there is a `IntegralType` column (`IntegerType`, `ShortType`, `ByteType`) that has null values the following exception is thrown:

    ValueError: Cannot convert non-finite values (NA or inf) to integer

This is because the null values first get converted to float NaN during the construction of the Pandas DataFrame in `from_records`, and then it is attempted to be converted back to to an integer where it fails.

The fix is going to check if the Pandas DataFrame can cause such failure when converting, if so, we don't do the conversion and use the inferred type by Pandas.

Closes #18945

## How was this patch tested?

Added pyspark test.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #19319 from viirya/SPARK-21766.
2017-09-22 22:39:47 +09:00
Bryan Cutler 27fc536d9a [SPARK-21190][PYSPARK] Python Vectorized UDFs
This PR adds vectorized UDFs to the Python API

**Proposed API**
Introduce a flag to turn on vectorization for a defined UDF, for example:

```
pandas_udf(DoubleType())
def plus(a, b)
    return a + b
```
or

```
plus = pandas_udf(lambda a, b: a + b, DoubleType())
```
Usage is the same as normal UDFs

0-parameter UDFs
pandas_udf functions can declare an optional `**kwargs` and when evaluated, will contain a key "size" that will give the required length of the output.  For example:

```
pandas_udf(LongType())
def f0(**kwargs):
    return pd.Series(1).repeat(kwargs["size"])

df.select(f0())
```

Added new unit tests in pyspark.sql that are enabled if pyarrow and Pandas are available.

- [x] Fix support for promoted types with null values
- [ ] Discuss 0-param UDF API (use of kwargs)
- [x] Add tests for chained UDFs
- [ ] Discuss behavior when pyarrow not installed / enabled
- [ ] Cleanup pydoc and add user docs

Author: Bryan Cutler <cutlerb@gmail.com>
Author: Takuya UESHIN <ueshin@databricks.com>

Closes #18659 from BryanCutler/arrow-vectorized-udfs-SPARK-21404.
2017-09-22 16:17:50 +08:00
Sean Owen e17901d6df [SPARK-22049][DOCS] Confusing behavior of from_utc_timestamp and to_utc_timestamp
## What changes were proposed in this pull request?

Clarify behavior of to_utc_timestamp/from_utc_timestamp with an example

## How was this patch tested?

Doc only change / existing tests

Author: Sean Owen <sowen@cloudera.com>

Closes #19276 from srowen/SPARK-22049.
2017-09-20 20:47:17 +09:00
Maciej Bryński f4073020ad [SPARK-22032][PYSPARK] Speed up StructType conversion
## What changes were proposed in this pull request?

StructType.fromInternal is calling f.fromInternal(v) for every field.
We can use precalculated information about type to limit the number of function calls. (its calculated once per StructType and used in per record calculations)

Benchmarks (Python profiler)
```
df = spark.range(10000000).selectExpr("id as id0", "id as id1", "id as id2", "id as id3", "id as id4", "id as id5", "id as id6", "id as id7", "id as id8", "id as id9", "struct(id) as s").cache()
df.count()
df.rdd.map(lambda x: x).count()
```

Before
```
310274584 function calls (300272456 primitive calls) in 1320.684 seconds

Ordered by: internal time, cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
 10000000  253.417    0.000  486.991    0.000 types.py:619(<listcomp>)
 30000000  192.272    0.000 1009.986    0.000 types.py:612(fromInternal)
100000000  176.140    0.000  176.140    0.000 types.py:88(fromInternal)
 20000000  156.832    0.000  328.093    0.000 types.py:1471(_create_row)
    14000  107.206    0.008 1237.917    0.088 {built-in method loads}
 20000000   80.176    0.000 1090.162    0.000 types.py:1468(<lambda>)
```

After
```
210274584 function calls (200272456 primitive calls) in 1035.974 seconds

Ordered by: internal time, cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
 30000000  215.845    0.000  698.748    0.000 types.py:612(fromInternal)
 20000000  165.042    0.000  351.572    0.000 types.py:1471(_create_row)
    14000  116.834    0.008  946.791    0.068 {built-in method loads}
 20000000   87.326    0.000  786.073    0.000 types.py:1468(<lambda>)
 20000000   85.477    0.000  134.607    0.000 types.py:1519(__new__)
 10000000   65.777    0.000  126.712    0.000 types.py:619(<listcomp>)
```

Main difference is types.py:619(<listcomp>) and types.py:88(fromInternal) (which is removed in After)
The number of function calls is 100 million less. And performance is 20% better.

Benchmark (worst case scenario.)

Test
```
df = spark.range(1000000).selectExpr("current_timestamp as id0", "current_timestamp as id1", "current_timestamp as id2", "current_timestamp as id3", "current_timestamp as id4", "current_timestamp as id5", "current_timestamp as id6", "current_timestamp as id7", "current_timestamp as id8", "current_timestamp as id9").cache()
df.count()
df.rdd.map(lambda x: x).count()
```

Before
```
31166064 function calls (31163984 primitive calls) in 150.882 seconds
```

After
```
31166064 function calls (31163984 primitive calls) in 153.220 seconds
```

IMPORTANT:
The benchmark was done on top of https://github.com/apache/spark/pull/19246.
Without https://github.com/apache/spark/pull/19246 the performance improvement will be even greater.

## How was this patch tested?

Existing tests.
Performance benchmark.

Author: Maciej Bryński <maciek-github@brynski.pl>

Closes #19249 from maver1ck/spark_22032.
2017-09-18 02:34:44 +09:00
goldmedal a28728a9af [SPARK-21513][SQL][FOLLOWUP] Allow UDF to_json support converting MapType to json for PySpark and SparkR
## What changes were proposed in this pull request?
In previous work SPARK-21513, we has allowed `MapType` and `ArrayType` of `MapType`s convert to a json string but only for Scala API. In this follow-up PR, we will make SparkSQL support it for PySpark and SparkR, too. We also fix some little bugs and comments of the previous work in this follow-up PR.

### For PySpark
```
>>> data = [(1, {"name": "Alice"})]
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(to_json(df.value).alias("json")).collect()
[Row(json=u'{"name":"Alice")']
>>> data = [(1, [{"name": "Alice"}, {"name": "Bob"}])]
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(to_json(df.value).alias("json")).collect()
[Row(json=u'[{"name":"Alice"},{"name":"Bob"}]')]
```
### For SparkR
```
# Converts a map into a JSON object
df2 <- sql("SELECT map('name', 'Bob')) as people")
df2 <- mutate(df2, people_json = to_json(df2$people))
# Converts an array of maps into a JSON array
df2 <- sql("SELECT array(map('name', 'Bob'), map('name', 'Alice')) as people")
df2 <- mutate(df2, people_json = to_json(df2$people))
```
## How was this patch tested?
Add unit test cases.

cc viirya HyukjinKwon

Author: goldmedal <liugs963@gmail.com>

Closes #19223 from goldmedal/SPARK-21513-fp-PySaprkAndSparkR.
2017-09-15 11:53:10 +09:00
Peter Szalai 520d92a191 [SPARK-20098][PYSPARK] dataType's typeName fix
## What changes were proposed in this pull request?
`typeName`  classmethod has been fixed by using type -> typeName map.

## How was this patch tested?
local build

Author: Peter Szalai <szalaipeti.vagyok@gmail.com>

Closes #17435 from szalai1/datatype-gettype-fix.
2017-09-10 17:47:45 +09:00
Yanbo Liang e4d8f9a36a [MINOR][SQL] Correct DataFrame doc.
## What changes were proposed in this pull request?
Correct DataFrame doc.

## How was this patch tested?
Only doc change, no tests.

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #19173 from yanboliang/df-doc.
2017-09-09 09:25:12 -07:00
hyukjinkwon 8598d03a00 [SPARK-15243][ML][SQL][PYTHON] Add missing support for unicode in Param methods & functions in dataframe
## What changes were proposed in this pull request?

This PR proposes to support unicodes in Param methods in ML, other missed functions in DataFrame.

For example, this causes a `ValueError` in Python 2.x when param is a unicode string:

```python
>>> from pyspark.ml.classification import LogisticRegression
>>> lr = LogisticRegression()
>>> lr.hasParam("threshold")
True
>>> lr.hasParam(u"threshold")
Traceback (most recent call last):
 ...
    raise TypeError("hasParam(): paramName must be a string")
TypeError: hasParam(): paramName must be a string
```

This PR is based on https://github.com/apache/spark/pull/13036

## How was this patch tested?

Unit tests in `python/pyspark/ml/tests.py` and `python/pyspark/sql/tests.py`.

Author: hyukjinkwon <gurwls223@gmail.com>
Author: sethah <seth.hendrickson16@gmail.com>

Closes #17096 from HyukjinKwon/SPARK-15243.
2017-09-08 11:57:33 -07:00
Takuya UESHIN 57bc1e9eb4 [SPARK-21950][SQL][PYTHON][TEST] pyspark.sql.tests.SQLTests2 should stop SparkContext.
## What changes were proposed in this pull request?

`pyspark.sql.tests.SQLTests2` doesn't stop newly created spark context in the test and it might affect the following tests.
This pr makes `pyspark.sql.tests.SQLTests2` stop `SparkContext`.

## How was this patch tested?

Existing tests.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #19158 from ueshin/issues/SPARK-21950.
2017-09-08 14:26:07 +09:00
hyukjinkwon 07fd68a29f [SPARK-21897][PYTHON][R] Add unionByName API to DataFrame in Python and R
## What changes were proposed in this pull request?

This PR proposes to add a wrapper for `unionByName` API to R and Python as well.

**Python**

```python
df1 = spark.createDataFrame([[1, 2, 3]], ["col0", "col1", "col2"])
df2 = spark.createDataFrame([[4, 5, 6]], ["col1", "col2", "col0"])
df1.unionByName(df2).show()
```

```
+----+----+----+
|col0|col1|col3|
+----+----+----+
|   1|   2|   3|
|   6|   4|   5|
+----+----+----+
```

**R**

```R
df1 <- select(createDataFrame(mtcars), "carb", "am", "gear")
df2 <- select(createDataFrame(mtcars), "am", "gear", "carb")
head(unionByName(limit(df1, 2), limit(df2, 2)))
```

```
  carb am gear
1    4  1    4
2    4  1    4
3    4  1    4
4    4  1    4
```

## How was this patch tested?

Doctests for Python and unit test added in `test_sparkSQL.R` for R.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #19105 from HyukjinKwon/unionByName-r-python.
2017-09-03 21:03:21 +09:00
hyukjinkwon 648a8626b8 [SPARK-21789][PYTHON] Remove obsolete codes for parsing abstract schema strings
## What changes were proposed in this pull request?

This PR proposes to remove private functions that look not used in the main codes, `_split_schema_abstract`, `_parse_field_abstract`, `_parse_schema_abstract` and `_infer_schema_type`.

## How was this patch tested?

Existing tests.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18647 from HyukjinKwon/remove-abstract.
2017-09-01 13:09:24 +09:00
hyukjinkwon 5cd8ea99f0 [SPARK-21779][PYTHON] Simpler DataFrame.sample API in Python
## What changes were proposed in this pull request?

This PR make `DataFrame.sample(...)` can omit `withReplacement` defaulting `False`, consistently with equivalent Scala / Java API.

In short, the following examples are allowed:

```python
>>> df = spark.range(10)
>>> df.sample(0.5).count()
7
>>> df.sample(fraction=0.5).count()
3
>>> df.sample(0.5, seed=42).count()
5
>>> df.sample(fraction=0.5, seed=42).count()
5
```

In addition, this PR also adds some type checking logics as below:

```python
>>> df = spark.range(10)
>>> df.sample().count()
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [].
>>> df.sample(True).count()
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [<type 'bool'>].
>>> df.sample(42).count()
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [<type 'int'>].
>>> df.sample(fraction=False, seed="a").count()
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [<type 'bool'>, <type 'str'>].
>>> df.sample(seed=[1]).count()
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [<type 'list'>].
>>> df.sample(withReplacement="a", fraction=0.5, seed=1)
...
TypeError: withReplacement (optional), fraction (required) and seed (optional) should be a bool, float and number; however, got [<type 'str'>, <type 'float'>, <type 'int'>].
```

## How was this patch tested?

Manually tested, unit tests added in doc tests and manually checked the built documentation for Python.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18999 from HyukjinKwon/SPARK-21779.
2017-09-01 13:01:23 +09:00
Liang-Chi Hsieh ecf437a648 [SPARK-21534][SQL][PYSPARK] PickleException when creating dataframe from python row with empty bytearray
## What changes were proposed in this pull request?

`PickleException` is thrown when creating dataframe from python row with empty bytearray

    spark.createDataFrame(spark.sql("select unhex('') as xx").rdd.map(lambda x: {"abc": x.xx})).show()

    net.razorvine.pickle.PickleException: invalid pickle data for bytearray; expected 1 or 2 args, got 0
    	at net.razorvine.pickle.objects.ByteArrayConstructor.construct(ByteArrayConstructor.java
        ...

`ByteArrayConstructor` doesn't deal with empty byte array pickled by Python3.

## How was this patch tested?

Added test.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #19085 from viirya/SPARK-21534.
2017-08-31 12:55:38 +09:00
Dongjoon Hyun d8f4540863 [SPARK-21839][SQL] Support SQL config for ORC compression
## What changes were proposed in this pull request?

This PR aims to support `spark.sql.orc.compression.codec` like Parquet's `spark.sql.parquet.compression.codec`. Users can use SQLConf to control ORC compression, too.

## How was this patch tested?

Pass the Jenkins with new and updated test cases.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #19055 from dongjoon-hyun/SPARK-21839.
2017-08-31 08:16:58 +09:00
vinodkc 51620e288b [SPARK-21756][SQL] Add JSON option to allow unquoted control characters
## What changes were proposed in this pull request?

This patch adds allowUnquotedControlChars option in JSON data source to allow JSON Strings to contain unquoted control characters (ASCII characters with value less than 32, including tab and line feed characters)

## How was this patch tested?
Add new test cases

Author: vinodkc <vinod.kc.in@gmail.com>

Closes #19008 from vinodkc/br_fix_SPARK-21756.
2017-08-25 10:18:03 -07:00
hyukjinkwon dc5d34d8dc [SPARK-19165][PYTHON][SQL] PySpark APIs using columns as arguments should validate input types for column
## What changes were proposed in this pull request?

While preparing to take over https://github.com/apache/spark/pull/16537, I realised a (I think) better approach to make the exception handling in one point.

This PR proposes to fix `_to_java_column` in `pyspark.sql.column`, which most of functions in `functions.py` and some other APIs use. This `_to_java_column` basically looks not working with other types than `pyspark.sql.column.Column` or string (`str` and `unicode`).

If this is not `Column`, then it calls `_create_column_from_name` which calls `functions.col` within JVM:

42b9eda80e/sql/core/src/main/scala/org/apache/spark/sql/functions.scala (L76)

And it looks we only have `String` one with `col`.

So, these should work:

```python
>>> from pyspark.sql.column import _to_java_column, Column
>>> _to_java_column("a")
JavaObject id=o28
>>> _to_java_column(u"a")
JavaObject id=o29
>>> _to_java_column(spark.range(1).id)
JavaObject id=o33
```

whereas these do not:

```python
>>> _to_java_column(1)
```
```
...
py4j.protocol.Py4JError: An error occurred while calling z:org.apache.spark.sql.functions.col. Trace:
py4j.Py4JException: Method col([class java.lang.Integer]) does not exist
    ...
```

```python
>>> _to_java_column([])
```
```
...
py4j.protocol.Py4JError: An error occurred while calling z:org.apache.spark.sql.functions.col. Trace:
py4j.Py4JException: Method col([class java.util.ArrayList]) does not exist
    ...
```

```python
>>> class A(): pass
>>> _to_java_column(A())
```
```
...
AttributeError: 'A' object has no attribute '_get_object_id'
```

Meaning most of functions using `_to_java_column` such as `udf` or `to_json` or some other APIs throw an exception as below:

```python
>>> from pyspark.sql.functions import udf
>>> udf(lambda x: x)(None)
```

```
...
py4j.protocol.Py4JJavaError: An error occurred while calling z:org.apache.spark.sql.functions.col.
: java.lang.NullPointerException
    ...
```

```python
>>> from pyspark.sql.functions import to_json
>>> to_json(None)
```

```
...
py4j.protocol.Py4JJavaError: An error occurred while calling z:org.apache.spark.sql.functions.col.
: java.lang.NullPointerException
    ...
```

**After this PR**:

```python
>>> from pyspark.sql.functions import udf
>>> udf(lambda x: x)(None)
...
```

```
TypeError: Invalid argument, not a string or column: None of type <type 'NoneType'>. For column literals, use 'lit', 'array', 'struct' or 'create_map' functions.
```

```python
>>> from pyspark.sql.functions import to_json
>>> to_json(None)
```

```
...
TypeError: Invalid argument, not a string or column: None of type <type 'NoneType'>. For column literals, use 'lit', 'array', 'struct' or 'create_map' functions.
```

## How was this patch tested?

Unit tests added in `python/pyspark/sql/tests.py` and manual tests.

Author: hyukjinkwon <gurwls223@gmail.com>
Author: zero323 <zero323@users.noreply.github.com>

Closes #19027 from HyukjinKwon/SPARK-19165.
2017-08-24 20:29:03 +09:00
Andrew Ray 10be01848e [SPARK-21566][SQL][PYTHON] Python method for summary
## What changes were proposed in this pull request?

Adds the recently added `summary` method to the python dataframe interface.

## How was this patch tested?

Additional inline doctests.

Author: Andrew Ray <ray.andrew@gmail.com>

Closes #18762 from aray/summary-py.
2017-08-18 18:10:54 -07:00
Nicholas Chammas 9660831050 [SPARK-21712][PYSPARK] Clarify type error for Column.substr()
Proposed changes:
* Clarify the type error that `Column.substr()` gives.

Test plan:
* Tested this manually.
* Test code:
    ```python
    from pyspark.sql.functions import col, lit
    spark.createDataFrame([['nick']], schema=['name']).select(col('name').substr(0, lit(1)))
    ```
* Before:
    ```
    TypeError: Can not mix the type
    ```
* After:
    ```
    TypeError: startPos and length must be the same type. Got <class 'int'> and
    <class 'pyspark.sql.column.Column'>, respectively.
    ```

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #18926 from nchammas/SPARK-21712-substr-type-error.
2017-08-16 11:19:15 +09:00
byakuinss 0fcde87aad [SPARK-21658][SQL][PYSPARK] Add default None for value in na.replace in PySpark
## What changes were proposed in this pull request?
JIRA issue: https://issues.apache.org/jira/browse/SPARK-21658

Add default None for value in `na.replace` since `Dataframe.replace` and `DataframeNaFunctions.replace` are alias.

The default values are the same now.
```
>>> df = sqlContext.createDataFrame([('Alice', 10, 80.0)])
>>> df.replace({"Alice": "a"}).first()
Row(_1=u'a', _2=10, _3=80.0)
>>> df.na.replace({"Alice": "a"}).first()
Row(_1=u'a', _2=10, _3=80.0)
```

## How was this patch tested?
Existing tests.

cc viirya

Author: byakuinss <grace.chinhanyu@gmail.com>

Closes #18895 from byakuinss/SPARK-21658.
2017-08-15 00:41:01 +09:00
bravo-zhang 84454d7d33 [SPARK-14932][SQL] Allow DataFrame.replace() to replace values with None
## What changes were proposed in this pull request?

Currently `df.na.replace("*", Map[String, String]("NULL" -> null))` will produce exception.
This PR enables passing null/None as value in the replacement map in DataFrame.replace().
Note that the replacement map keys and values should still be the same type, while the values can have a mix of null/None and that type.
This PR enables following operations for example:
`df.na.replace("*", Map[String, String]("NULL" -> null))`(scala)
`df.na.replace("*", Map[Any, Any](60 -> null, 70 -> 80))`(scala)
`df.na.replace('Alice', None)`(python)
`df.na.replace([10, 20])`(python, replacing with None is by default)
One use case could be: I want to replace all the empty strings with null/None because they were incorrectly generated and then drop all null/None data
`df.na.replace("*", Map("" -> null)).na.drop()`(scala)
`df.replace(u'', None).dropna()`(python)

## How was this patch tested?

Scala unit test.
Python doctest and unit test.

Author: bravo-zhang <mzhang1230@gmail.com>

Closes #18820 from bravo-zhang/spark-14932.
2017-08-09 17:42:21 -07:00
Mac 4f7ec3a316 [SPARK][DOCS] Added note on meaning of position to substring function
## What changes were proposed in this pull request?

Enhanced some existing documentation

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: Mac <maclockard@gmail.com>

Closes #18710 from maclockard/maclockard-patch-1.
2017-08-07 17:16:03 +01:00
hyukjinkwon b56f79cc35 [SPARK-20090][PYTHON] Add StructType.fieldNames in PySpark
## What changes were proposed in this pull request?

This PR proposes `StructType.fieldNames` that returns a copy of a field name list rather than a (undocumented) `StructType.names`.

There are two points here:

  - API consistency with Scala/Java

  - Provide a safe way to get the field names. Manipulating these might cause unexpected behaviour as below:

    ```python
    from pyspark.sql.types import *

    struct = StructType([StructField("f1", StringType(), True)])
    names = struct.names
    del names[0]
    spark.createDataFrame([{"f1": 1}], struct).show()
    ```

    ```
    ...
    java.lang.IllegalStateException: Input row doesn't have expected number of values required by the schema. 1 fields are required while 0 values are provided.
    	at org.apache.spark.sql.execution.python.EvaluatePython$.fromJava(EvaluatePython.scala:138)
    	at org.apache.spark.sql.SparkSession$$anonfun$6.apply(SparkSession.scala:741)
    	at org.apache.spark.sql.SparkSession$$anonfun$6.apply(SparkSession.scala:741)
    ...
    ```

## How was this patch tested?

Added tests in `python/pyspark/sql/tests.py`.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18618 from HyukjinKwon/SPARK-20090.
2017-07-28 20:59:32 -07:00
Takuya UESHIN 2ff35a057e [SPARK-21440][SQL][PYSPARK] Refactor ArrowConverters and add ArrayType and StructType support.
## What changes were proposed in this pull request?

This is a refactoring of `ArrowConverters` and related classes.

1. Refactor `ColumnWriter` as `ArrowWriter`.
2. Add `ArrayType` and `StructType` support.
3. Refactor `ArrowConverters` to skip intermediate `ArrowRecordBatch` creation.

## How was this patch tested?

Added some tests and existing tests.

Author: Takuya UESHIN <ueshin@databricks.com>

Closes #18655 from ueshin/issues/SPARK-21440.
2017-07-27 19:19:51 +08:00
gatorsmile ebc24a9b7f [SPARK-20586][SQL] Add deterministic to ScalaUDF
### What changes were proposed in this pull request?
Like [Hive UDFType](https://hive.apache.org/javadocs/r2.0.1/api/org/apache/hadoop/hive/ql/udf/UDFType.html), we should allow users to add the extra flags for ScalaUDF and JavaUDF too. _stateful_/_impliesOrder_ are not applicable to our Scala UDF. Thus, we only add the following two flags.

- deterministic: Certain optimizations should not be applied if UDF is not deterministic. Deterministic UDF returns same result each time it is invoked with a particular input. This determinism just needs to hold within the context of a query.

When the deterministic flag is not correctly set, the results could be wrong.

For ScalaUDF in Dataset APIs, users can call the following extra APIs for `UserDefinedFunction` to make the corresponding changes.
- `nonDeterministic`: Updates UserDefinedFunction to non-deterministic.

Also fixed the Java UDF name loss issue.

Will submit a separate PR for `distinctLike`  for UDAF

### How was this patch tested?
Added test cases for both ScalaUDF

Author: gatorsmile <gatorsmile@gmail.com>
Author: Wenchen Fan <cloud0fan@gmail.com>

Closes #17848 from gatorsmile/udfRegister.
2017-07-25 17:19:44 -07:00
Xiang Gao b7a40f64e6 [SPARK-16542][SQL][PYSPARK] Fix bugs about types that result an array of null when creating DataFrame using python
## What changes were proposed in this pull request?
This is the reopen of https://github.com/apache/spark/pull/14198, with merge conflicts resolved.

ueshin Could you please take a look at my code?

Fix bugs about types that result an array of null when creating DataFrame using python.

Python's array.array have richer type than python itself, e.g. we can have `array('f',[1,2,3])` and `array('d',[1,2,3])`. Codes in spark-sql and pyspark didn't take this into consideration which might cause a problem that you get an array of null values when you have `array('f')` in your rows.

A simple code to reproduce this bug is:

```
from pyspark import SparkContext
from pyspark.sql import SQLContext,Row,DataFrame
from array import array

sc = SparkContext()
sqlContext = SQLContext(sc)

row1 = Row(floatarray=array('f',[1,2,3]), doublearray=array('d',[1,2,3]))
rows = sc.parallelize([ row1 ])
df = sqlContext.createDataFrame(rows)
df.show()
```

which have output

```
+---------------+------------------+
|    doublearray|        floatarray|
+---------------+------------------+
|[1.0, 2.0, 3.0]|[null, null, null]|
+---------------+------------------+
```

## How was this patch tested?

New test case added

Author: Xiang Gao <qasdfgtyuiop@gmail.com>
Author: Gao, Xiang <qasdfgtyuiop@gmail.com>
Author: Takuya UESHIN <ueshin@databricks.com>

Closes #18444 from zasdfgbnm/fix_array_infer.
2017-07-20 12:46:06 +09:00
hyukjinkwon 4ce735eed1 [SPARK-21394][SPARK-21432][PYTHON] Reviving callable object/partial function support in UDF in PySpark
## What changes were proposed in this pull request?

This PR proposes to avoid `__name__` in the tuple naming the attributes assigned directly from the wrapped function to the wrapper function, and use `self._name` (`func.__name__` or `obj.__class__.name__`).

After SPARK-19161, we happened to break callable objects as UDFs in Python as below:

```python
from pyspark.sql import functions

class F(object):
    def __call__(self, x):
        return x

foo = F()
udf = functions.udf(foo)
```

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../spark/python/pyspark/sql/functions.py", line 2142, in udf
    return _udf(f=f, returnType=returnType)
  File ".../spark/python/pyspark/sql/functions.py", line 2133, in _udf
    return udf_obj._wrapped()
  File ".../spark/python/pyspark/sql/functions.py", line 2090, in _wrapped
    functools.wraps(self.func)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/functools.py", line 33, in update_wrapper
    setattr(wrapper, attr, getattr(wrapped, attr))
AttributeError: F instance has no attribute '__name__'
```

This worked in Spark 2.1:

```python
from pyspark.sql import functions

class F(object):
    def __call__(self, x):
        return x

foo = F()
udf = functions.udf(foo)
spark.range(1).select(udf("id")).show()
```

```
+-----+
|F(id)|
+-----+
|    0|
+-----+
```

**After**

```python
from pyspark.sql import functions

class F(object):
    def __call__(self, x):
        return x

foo = F()
udf = functions.udf(foo)
spark.range(1).select(udf("id")).show()
```

```
+-----+
|F(id)|
+-----+
|    0|
+-----+
```

_In addition, we also happened to break partial functions as below_:

```python
from pyspark.sql import functions
from functools import partial

partial_func = partial(lambda x: x, x=1)
udf = functions.udf(partial_func)
```

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../spark/python/pyspark/sql/functions.py", line 2154, in udf
    return _udf(f=f, returnType=returnType)
  File ".../spark/python/pyspark/sql/functions.py", line 2145, in _udf
    return udf_obj._wrapped()
  File ".../spark/python/pyspark/sql/functions.py", line 2099, in _wrapped
    functools.wraps(self.func, assigned=assignments)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/functools.py", line 33, in update_wrapper
    setattr(wrapper, attr, getattr(wrapped, attr))
AttributeError: 'functools.partial' object has no attribute '__module__'
```

This worked in Spark 2.1:

```python
from pyspark.sql import functions
from functools import partial

partial_func = partial(lambda x: x, x=1)
udf = functions.udf(partial_func)
spark.range(1).select(udf()).show()
```

```
+---------+
|partial()|
+---------+
|        1|
+---------+
```

**After**

```python
from pyspark.sql import functions
from functools import partial

partial_func = partial(lambda x: x, x=1)
udf = functions.udf(partial_func)
spark.range(1).select(udf()).show()
```

```
+---------+
|partial()|
+---------+
|        1|
+---------+
```

## How was this patch tested?

Unit tests in `python/pyspark/sql/tests.py` and manual tests.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18615 from HyukjinKwon/callable-object.
2017-07-17 00:37:36 -07:00
hyukjinkwon ebc124d4c4 [SPARK-21365][PYTHON] Deduplicate logics parsing DDL type/schema definition
## What changes were proposed in this pull request?

This PR deals with four points as below:

- Reuse existing DDL parser APIs rather than reimplementing within PySpark

- Support DDL formatted string, `field type, field type`.

- Support case-insensitivity for parsing.

- Support nested data types as below:

  **Before**
  ```
  >>> spark.createDataFrame([[[1]]], "struct<a: struct<b: int>>").show()
  ...
  ValueError: The strcut field string format is: 'field_name:field_type', but got: a: struct<b: int>
  ```

  ```
  >>> spark.createDataFrame([[[1]]], "a: struct<b: int>").show()
  ...
  ValueError: The strcut field string format is: 'field_name:field_type', but got: a: struct<b: int>
  ```

  ```
  >>> spark.createDataFrame([[1]], "a int").show()
  ...
  ValueError: Could not parse datatype: a int
  ```

  **After**
  ```
  >>> spark.createDataFrame([[[1]]], "struct<a: struct<b: int>>").show()
  +---+
  |  a|
  +---+
  |[1]|
  +---+
  ```

  ```
  >>> spark.createDataFrame([[[1]]], "a: struct<b: int>").show()
  +---+
  |  a|
  +---+
  |[1]|
  +---+
  ```

  ```
  >>> spark.createDataFrame([[1]], "a int").show()
  +---+
  |  a|
  +---+
  |  1|
  +---+
  ```

## How was this patch tested?

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18590 from HyukjinKwon/deduplicate-python-ddl.
2017-07-11 22:03:10 +08:00
hyukjinkwon d4d9e17b31 [SPARK-20456][PYTHON][FOLLOWUP] Fix timezone-dependent doctests in unix_timestamp and from_unixtime
## What changes were proposed in this pull request?

This PR proposes to simply ignore the results in examples that are timezone-dependent in `unix_timestamp` and `from_unixtime`.

```
Failed example:
    time_df.select(unix_timestamp('dt', 'yyyy-MM-dd').alias('unix_time')).collect()
Expected:
    [Row(unix_time=1428476400)]
Got:unix_timestamp
    [Row(unix_time=1428418800)]
```

```
Failed example:
    time_df.select(from_unixtime('unix_time').alias('ts')).collect()
Expected:
    [Row(ts=u'2015-04-08 00:00:00')]
Got:
    [Row(ts=u'2015-04-08 16:00:00')]
```

## How was this patch tested?

Manually tested and `./run-tests --modules pyspark-sql`.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18597 from HyukjinKwon/SPARK-20456.
2017-07-11 15:23:03 +09:00
Bryan Cutler d03aebbe65 [SPARK-13534][PYSPARK] Using Apache Arrow to increase performance of DataFrame.toPandas
## What changes were proposed in this pull request?
Integrate Apache Arrow with Spark to increase performance of `DataFrame.toPandas`.  This has been done by using Arrow to convert data partitions on the executor JVM to Arrow payload byte arrays where they are then served to the Python process.  The Python DataFrame can then collect the Arrow payloads where they are combined and converted to a Pandas DataFrame.  Data types except complex, date, timestamp, and decimal  are currently supported, otherwise an `UnsupportedOperation` exception is thrown.

Additions to Spark include a Scala package private method `Dataset.toArrowPayload` that will convert data partitions in the executor JVM to `ArrowPayload`s as byte arrays so they can be easily served.  A package private class/object `ArrowConverters` that provide data type mappings and conversion routines.  In Python, a private method `DataFrame._collectAsArrow` is added to collect Arrow payloads and a SQLConf "spark.sql.execution.arrow.enable" can be used in `toPandas()` to enable using Arrow (uses the old conversion by default).

## How was this patch tested?
Added a new test suite `ArrowConvertersSuite` that will run tests on conversion of Datasets to Arrow payloads for supported types.  The suite will generate a Dataset and matching Arrow JSON data, then the dataset is converted to an Arrow payload and finally validated against the JSON data.  This will ensure that the schema and data has been converted correctly.

Added PySpark tests to verify the `toPandas` method is producing equal DataFrames with and without pyarrow.  A roundtrip test to ensure the pandas DataFrame produced by pyspark is equal to a one made directly with pandas.

Author: Bryan Cutler <cutlerb@gmail.com>
Author: Li Jin <ice.xelloss@gmail.com>
Author: Li Jin <li.jin@twosigma.com>
Author: Wes McKinney <wes.mckinney@twosigma.com>

Closes #18459 from BryanCutler/toPandas_with_arrow-SPARK-13534.
2017-07-10 15:21:03 -07:00
hyukjinkwon 2bfd5accdc [SPARK-21266][R][PYTHON] Support schema a DDL-formatted string in dapply/gapply/from_json
## What changes were proposed in this pull request?

This PR supports schema in a DDL formatted string for `from_json` in R/Python and `dapply` and `gapply` in R, which are commonly used and/or consistent with Scala APIs.

Additionally, this PR exposes `structType` in R to allow working around in other possible corner cases.

**Python**

`from_json`

```python
from pyspark.sql.functions import from_json

data = [(1, '''{"a": 1}''')]
df = spark.createDataFrame(data, ("key", "value"))
df.select(from_json(df.value, "a INT").alias("json")).show()
```

**R**

`from_json`

```R
df <- sql("SELECT named_struct('name', 'Bob') as people")
df <- mutate(df, people_json = to_json(df$people))
head(select(df, from_json(df$people_json, "name STRING")))
```

`structType.character`

```R
structType("a STRING, b INT")
```

`dapply`

```R
dapply(createDataFrame(list(list(1.0)), "a"), function(x) {x}, "a DOUBLE")
```

`gapply`

```R
gapply(createDataFrame(list(list(1.0)), "a"), "a", function(key, x) { x }, "a DOUBLE")
```

## How was this patch tested?

Doc tests for `from_json` in Python and unit tests `test_sparkSQL.R` in R.

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #18498 from HyukjinKwon/SPARK-21266.
2017-07-10 10:40:03 -07:00
Michael Patterson f5f02d213d [SPARK-20456][DOCS] Add examples for functions collection for pyspark
## What changes were proposed in this pull request?

This adds documentation to many functions in pyspark.sql.functions.py:
`upper`, `lower`, `reverse`, `unix_timestamp`, `from_unixtime`, `rand`, `randn`, `collect_list`, `collect_set`, `lit`
Add units to the trigonometry functions.
Renames columns in datetime examples to be more informative.
Adds links between some functions.

## How was this patch tested?

`./dev/lint-python`
`python python/pyspark/sql/functions.py`
`./python/run-tests.py --module pyspark-sql`

Author: Michael Patterson <map222@gmail.com>

Closes #17865 from map222/spark-20456.
2017-07-07 23:59:34 -07:00